package dep.web.servlet;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.Method;

public class BaseServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取请求路径
        String uri = req.getRequestURI();
        //2.获取方法名称
        String methodName = uri.substring(uri.lastIndexOf('/')+1);
        //获取方法对象Method,谁调用我，this就指向调用者
        try{
            //获取方法
            Method method = this.getClass().getMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);
            //执行方法
            method.invoke(this,req,resp);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    /*
    * 将对象转化为json，返回给客户端
    * */
    public void writeValue(Object obj, HttpServletResponse response) throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        response.setContentType("application/json;charset=utf-8");
        mapper.writeValue(response.getOutputStream(),obj);
    }
    public String writeValueAsString(Object obj) throws JsonProcessingException {
        ObjectMapper mapper = new ObjectMapper();
        return mapper.writeValueAsString(obj);
    }
}
